Prognostic Meteorological Discussion
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FXUS02 KWBC 131553
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1052 AM EST SAT FEB 13 2016

VALID 12Z TUE FEB 16 2016 - 12Z SAT FEB 20 2016

...WINTRY PATTERN FOR THE NORTHEAST QUARTER OF THE COUNTRY---EARLY
NEXT WEEK...

THE 13/00Z DETERMINISTIC FORECAST CYCLE GUIDANCE SEEMED TO BE
NARROWING DOWN THE OPTIONS --- FOR THE EASTERN UPPER-LEVEL
TROUGH`S EXIT ACROSS NEW ENGLAND --- BUT AGAIN PREFER MORE OF THE
ECENS...GEFS AND NAEFS MEANS APPROACH.

THE LEAD SURFACE WAVE AND MID-LEVEL SUPPORT MIGRATING NORTHWARD
--- ALONG AND EAST OF THE APPALACHIAN TRAIL ON MONDAY
NIGHT-TUESDAY --- IS THEN FOLLOWED BY A `CLEAN-UP` WAVE AND
CLIPPER-TYPE SYSTEM (FOR TUESDAY/TUESDAY NIGHT) ARCING IN
COUNTER-CLOCKWISE FASHION THROUGH THE LOWER HALF OF THE OHIO
VALLEY...SOUTHERN APPALACHIA AND THE DELMARVA --- WITHIN THE BASE
OF THIS PARTICULAR MID-LEVEL TROUGH. THIS `CLIPPER` TRACKS ALONG
THE BENCHMARK --- AND BRIEFLY ACROSS THE GULF OF MAINE WEDNESDAY
AND THURSDAY --- BEFORE WEAKENING INVOF ATLANTIC CANADA.

THE LEAD WAVE HAS `SPED UP` CONSIDERABLY FROM JUST 24 HOURS.
YESTERDAY TRIED TO LEAN FASTER AND TO A COLDER SOLUTION (A
PREFERRED 12/12Z GFS APPROACH AT THE SURFACE) TO OFFER A BETTER
COMPROMISE WITH THE VERY SLOW ECMWF SOLUTION. AND FOR THIS 13/00Z
CYCLE ---THE 13/00Z DETERMINISTIC ECMWF/GFS WERE A LITTLE BETTER
WITH THE SURFACE LOW TRACK ACROSS VERMONT AND LOCATION (JUST EAST
OF THE HUDSON VALLEY_AT 17/12Z). BUT ... THE ECMWF STILL LOOKS A
TAD WARMER THAN THE GFS --- AND IT`S A MUCH FASTER SOLUTION NOW
VERSUS 24 HOURS AGO. BOTH SOLUTIONS OFFERED YESTERDAY WERE SLOWER
THAN THE 13/00Z RUNS---AND BECAUSE THE 13/00Z ECMWF/GFS ARE FASTER
--- THE SURFACE WAVE SOLUTION HAS LESS TIME TO `WRAP UP` AND IS A
SOMEWHAT WEAKER VARIATION (BY 10-12MBS) NOW. THIS INDICATES THAT
THERE MAY NOT BE MUCH WARM ADVECTION WRAPPING INLAND OFF THE
WESTERN SHORES OF THE ATLANTIC AS THE WAVE GAINS LATITUDE ALONG
ITS STORM TRACK. I`M NOT ONE FOR CHASING MODEL RUNS --- BUT STILL
THINK THE POTENTIAL FOR A DECENT OVER-RUNNING WINTER P-TYPE SETUP
ALONG THE ENTIRE STRETCH OF THE APPALACHIAN TRAIL. BUT PERHAPS
THIS OVER-RUNNING SCENARIO STRETCHES QUICKER INTO THE NORTHERN
HALF OF THE TRAIL (PA TO ME) AND SNOWS DEVELOP A TAD QUICKER THAN
PREVIOUSLY FORECAST. SO STILL LEANING GFS ---THROUGH DAY 4 --- IF
ANY SMALLER SCALE DETAILS WERE HELPFUL IN THE THERMAL FIELDS (EAST
OF THE APPALACHIANS).

FROM 18/00Z TO 19/12Z ---
WILL CONTINUE USING THE 13/00Z ECENS...NAEFS AND GEFS APPROACH FOR
THE NEXT PACIFIC SYSTEM AND LEE-SIDE CYCLONE EMERGING ACROSS
SOUTHEAST ALBERTA AND MIGRATION EASTWARD INTO WESTERN LAKE
SUPERIOR/UPPER REACHES OF THE MISSISSIPPI RIVER (NORTH CENTRAL
MINNESOTA). BUT ATTEMPTED TO SHIFT THE BLEND `EMPHASIS` TO A MORE
HEAVILY-WEIGHTED NAEFS/GEFS --- GIVEN THE 13/00Z ECENS/ECMWF
SOLUTION ON/AFTER 19/00Z (THE DAY 6-7 SOLUTION) WEST OF THE
CONTINENTAL DIVIDE. EAST OF THE MISSISSIPPI --- THIS SYSTEM WILL
LIKELY PULL SOME ADDITIONAL COLD CANADIAN AIRMASS INTO THE GREAT
LAKES AND SOUTHWARD TO THE OHIO VALLEY---BUT GENERATE SOME WARMING
AND A SOUTH TO SOUTHWEST FLOW AHEAD OF THE FRONT.

THE 13/00Z ECENS/ECMWF IS A SOMEWHAT FLATTER/WEAKER AND SLIGHTLY
SLOWER SOLUTION WITH THE TROUGH MIGRATION EAST OF 140W.
SURPRISINGLY ... BY DAY 8 ... THE ECENS/GEFS/NAEFS LOOKED MUCH
BETTER ALONG 135W --- BUT ARE VERY MUCH OUT OF PHASE DOWNSTREAM
BETWEEN 100W-80W (AT 500 MBS). AN PRIMARILY BECAUSE OF THE
DIFFERENCES --- AT DAY 6-7 ALONG THE WEST COAST --- BETWEEN THE
FLATTER VERSUS MORE AMPLIFIED SOLUTIONS.

WETTER SECTIONS OF THE COUNTRY THIS FORECAST PERIOD WILL BE THE
NORTHEAST AND NORTHWEST QUARTERS OF THE COUNTRY.

VOJTESAK


$$





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